The present invention relates generally to hand-held power tools employing reciprocating working action, such as jigsaws or saber saws, and particularly to jigsaws capable of orbital cutting action.
It is known to provide jigsaws with orbital motion, in which the normally vertically reciprocating blade exerts a forward or lateral component of the cutting stroke. This type of orbital motion has been known to provide more effective cutting action.
One design criterion of such saws is that the main plunger, the shaft-like component to which the blade is attached and which reciprocates to provide the cutting motion, is also permitted a specified degree of forward and rearward play to effect orbital motion.
It is also known to provide such tools with scroll cutting capability for making intricate designs and other projects involving tight cutting parameters. To date, tools that were capable of both scroll cutting or orbital cutting had a mechanism design such that control location of the orbital motion was at the top of the plunger. A drawback of this location is that insufficient mechanical force is applied to the rear of the blade to provide strong cutting action during the orbital stroke. In this manner, the potential cutting improvements of orbital cutting are not achieved.
Another drawback of this control location is that due to the relatively long length of the plungers, the provision of the pendulum-like orbital option often introduces flex and play in the operation of the plunger. This relatively large amount of flex makes it more difficult to accurately control the movement of the lower end of the plunger, which is also the attachment point of the blade. The result is cutting inefficiency and/or inaccuracy.
This relatively large amount of forward and backward flex in the plunger is caused by a swivel support typically fixed to the tool housing. The swivel support is rotated by an eccentric to exert a lateral biasing force on a rear or non-cutting edge of the blade. Additionally, the placement of the swivel support at the tool housing results in another drawback, the swivel support prevents the cutting device from being able to do scrolling and orbital cutting with the same tool through a selector switch.
Thus, there is a need for a jigsaw or similar cutting device which addresses the issue of support for the pendulum movement of the plunger for more accurate and effective orbital cutting and which can provide both scroll cutting and orbital cutting motion.